Last week the National Transportation and Safety Board (NTSB) issued a recommendation that state governments ban hands-free, as well as hands-on, mobile device use while driving. The recommendation doesn’t have the force of law, but the NTSB’s pronouncements are influential.

There’s no doubt that distracted driving can lead to car accidents that injure or kill, and the recommended ban is certainly well intended. But the NTSB may not be doing the right thing. An educational campaign to change driver’s habits would be a much better approach.

First, how big of a concern is mobile device use exactly? If you’ve lost a loved one to a crash caused by texting or emailing, that question might sound insulting. However, policy makers are entrusted with putting emotions aside and making cooly rational decisions that increase the net welfare of society.

A new report, coincidentally released the same day as the NTSB’s recommendation, shows that the methodologies of two influential studies on distracted driving were problematic and they likely overstated the risk of car crash from distraction. But let’s put the studies aside and look at the cost of distracted driving as the NTSB says we should.

The NTSB fact sheet that accompanied the ban’s release notes that there were just over 3,000 “distraction-affected” crashes last year. But what does that tell us?

The figure comes from the National Highway Traffic Safety Administration’s annual injury and fatality report, which also reported that 2010 saw a record-breaking decline in traffic fatalities. Crash deaths are down to the lowest levels in 60 years even though in those six decades the population has doubled and American drivers now travel almost 46 billion more miles a year. Additionally, the report’s “distraction-affected” crashes include those caused by distractions other than mobile devices. And due to a narrowing of the methodology for counting distraction-affected crashes, the 2010 count of 3,092 is actually less than the 2009 count of 5,474.

While 3,000 deaths is nothing to take lightly, it’s difficult to know from that number alone what we should be willing to give up to eliminate the risk of distracted drivers. All choices have costs. While we could eliminate almost all traffic fatalities by banning driving outright, we know that’s a ridiculous proposition because the cost of that choice is too high even though it would save tens of thousands of lives.